March 2000 arXiv papers — page 22

Mingliang Cai, Gregory J. Galloway

In hep-th/9910245, Witten and Yau consider the AdS/CFT correspondence in the context of a Riemannian Einstein manifold $M^{n+1}$ of negative Ricci curvature which admits a conformal compactification with conformal boundary $N^n$. They prove that if the conformal class of the boundary contains a metric of positive scalar curvature, then $M$ and $N$ have sever

S. Ying

The observed electromagnetic (EM) properties of a nucleon at high energy are studied to search for a possible metastable color superconducting phase, called a virtual phase, that has an energy density close to the true ground state of the vacuum. The discussion is based on a mechanism of spontaneous partial breaking of the EM U(1) gauge symmetry inside a col

Zoltan Kunszt

I discuss two aspects of the electroweak interactions: the status of the precision measurement of the electroweak parameters and their impact on the Higgs search at future colliders.

E. Norrbin, R. Vogt

We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward

K. Matsuda, N. Takeda, T. Fukuyama, H. Nishiura

We examine the constraints on the MNS lepton mixing matrix from the present and future experimental data of the neutrino oscillation and lepton number violation processes. We introduce a graphical representation of the CP violation phases which appear in the lepton number violation processes such as neutrinoless double beta decay, the $μ^--e^+$ conversion, a

Christof Gattringer

We expand the most general lattice Dirac operator D in a basis of simple operators. The Ginsparg-Wilson equation turns into a system of coupled quadratic equations for the expansion coefficients. Our expansion of D allows for a natural cutoff and the remaining quadratic equations can be solved numerically. The procedure allows to find Dirac operators which o

Murray Moinester, Suh Urk Chung

We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiative transition studies. We review here the physics motivation for this program. We describe the beam, detector, trigger requirements, and

Bahram Mashhoon

The gravitational couplings of intrinsic spin are briefly reviewed. A consequence of the Dirac equation in the exterior gravitational field of a rotating mass is considered in detail, namely, the difference in the energy of a spin-1/2 particle polarized vertically up and down near the surface of a rotating body is $\hbarΩ\sinθ$. Here $θ$ is the latitude and

L. Fatibene, M. Ferraris, M. Francaviglia, M. Raiteri

The Lagrangian proposed by York et al. and the covariant first order Lagrangian for General Relativity are introduced to deal with the (vacuum) gravitational field on a reference background. The two Lagrangians are compared and we show that the first one can be obtained from the latter under suitable hypotheses. The induced variational principles are also co

Naresh Dadhich

In the spirit of the Newtonian theory, we characterize spherically symmetric empty space in general relativity in terms of energy density measured by a static observer and convergence density experienced by null and timelike congruences. It turns out that space surrounding a static particle is entirely specified by vanishing of energy and null convergence de

Marc Denecker

The goal of this paper is to extend classical logic with a generalized notion of inductive definition supporting positive and negative induction, to investigate the properties of this logic, its relationships to other logics in the area of non-monotonic reasoning, logic programming and deductive databases, and to show its application for knowledge representa

I. Stephan, F. Saubion, P. Nicolas

This article describes the first implementation of the GADEL system : a Genetic Algorithm for Default Logic. The goal of GADEL is to compute extensions in Reiter's default logic. It accepts every kind of finite propositional default theories and is based on evolutionary principles of Genetic Algorithms. Its first experimental results on certain instances

Daniele Theseider Dupre'

Diagnostic reasoning has been characterized logically as consistency-based reasoning or abductive reasoning. Previous analyses in the literature have shown, on the one hand, that choosing the (in general more restrictive) abductive definition may be appropriate or not, depending on the content of the knowledge base [Console&Torasso91], and, on the other hand

G. Antoniou, D. Billigton, G. Governatori, M. J. Maher

Logics for knowledge representation suffer from over-specialization: while each logic may provide an ideal representation formalism for some problems, it is less than optimal for others. A solution to this problem is to choose from several logics and, when necessary, combine the representations. In general, such an approach results in a very difficult proble

Anupam Garg

The magnetic molecule Fe_8 has been predicted and observed to have a rich pattern of degeneracies in its spectrum as an external magnetic field is varied. These degeneracies have now been recognized to be diabolical points. This paper analyzes the diabolicity and all essential properties of this system using elementary perturbation theory. A variety of argum

A. Minguzzi, M. P. Tosi

We discuss the ground state and the small-amplitude excitations of dilute boson-fermion mixtures confined in spherical harmonic traps at $T = 0$, assuming repulsive boson-boson interactions and with each component being in a single hyperfine state. From previous studies of the equilibrium density profiles we propose a schematic phase diagram in a plane defin

Claudio Castellano, Matteo Marsili, Alessandro Vespignani

We present extensive numerical simulations of the Axelrod's model for social influence, aimed at understanding the formation of cultural domains. This is a nonequilibrium model with short range interactions and a remarkably rich dynamical behavior. We study the phase diagram of the model and uncover a nonequilibrium phase transition separating an ordered

Anna Minguzzi, Patrizia Vignolo, Mario P. Tosi

We use a semiclassical two-fluid model to study the momentum distribution of a Bose-condensed gas with repulsive interactions inside a harmonic trap at finite temperature, with specific focus on atomic hydrogen. We give particular attention to the average kinetic energy, which is almost entirely associated with the thermal cloud. A non-linear dependence of t

C. B. Hanna, Dylan Haas, J. C. Diaz-Velez

We investigate theoretically the effects of intralayer and interlayer exchange in biased double-layer electron and hole systems, in the absence of a magnetic field. We use a variational Hartree-Fock-like approximation to analyze the effects of layer separation, layer density, tunneling, and applied gate voltages on the layer densities and on interlayer phase

M. Reza Sadr-Lahijany, Purusattam Ray, H. E. Stanley

We study the behavior of the topological defects in the inherent structures of a two-dimensional binary Lennard-Jones system as the size dispersity varies. We find that topological defects arising from the particle size dispersity are responsible for destabilizing the solid as follows: (i) for particle density $ρ\leq 0.9$, the solid melts through intermediat

Georgios Varelogiannis

We report a complete multicomponent mean-field-theory for the coexistence and competition of charge ordering (CO), antiferromagnetic (AFM) and ferromagnetic (FM) spin ordering in the presence of a uniform magnetic field. Doping the AFM or CO state always generates a ferromagnetic component. Itinerant FM, AFM and CO, necessarily coexist and compete in a parti

Sven E. Krueger, Dirk Schmalfuss, Johannes Richter

While the diagonalization of a quadratic bosonic form can always be done using a Bogoliubov transformation, the practical implementation for systems with a large number of different bosons is a tedious analytical task. Here we use the coupled cluster method (CCM) to exactly diagonalise such complicated quadratic forms. This yields to a straightforward algori

Dirk Helbing, Tadeusz Platkowski

We present a simple discrete model for the non-linear spatial interaction of different kinds of ``subpopulations'' composed of identical moving entities like particles, bacteria, individuals, etc. The model allows to mimic a variety of self-organized agglomeration and segregation phenomena. By relating it to game-theoretical ideas, it can be applied

P. Mosconi, A. Rigamonti, A. A. Varlamov

The dependence of the Maki-Thompson (MT) and of the density of states depletion (DOS) contributions from superconducting fluctuations (SF) to NMR-NQR relaxation is derived in the framework of the diagrammatic theory, applied to layered three dimensional (3D) high T_c superconductors. The regularization procedure devised for the conductivity (Buzdin and Varla

Jun Koide

A systematic derivation of Boltzmann equation is presented in the framework of closed-time-path formalism. Introducing a new type of probe, the expectation value of number operator is calculated as a functional of source. Then solving for the source by inverting the relation, the equation of motion for number is obtained when the source is removed, and it tu

R. S. Gonnelli, V. A. Stepanov, A. Morello, G. A. Ummarino

We present and discuss the results of measurements of the ab-plane resistivity of La_{2-x}Sr_{x}CuO_{4} single crystals with small Sr contents (x=0.052-0.075). The resistivity was obtained in the temperature range between 4.2 K and 300 K by using an AC Van der Pauw technique. When the temperature is lowered, the rho_{ab}(T) curves show a transition from a li

K. Y. Michael Wong, Hidetoshi Nishimori

We consider the problems of error-correcting codes and image restoration with multiple stages of dynamics. Information extracted from the former stage can be used selectively to improve the performance of the latter one. Analytic results were derived for the mean-field systems using the cavity method. We find that it has the advantage of being tolerant to un

R. A. Broglia, G. Tiana

With the help of lattice Monte Carlo modelling of heteropolymers, we show that the necessary condition for a protein to fold on short call is to proceed through partially folded intermediates. These elementary structures are formed at an early stage in the folding process and contain, at the local level, essentially all of the amino acids found in the foldin

I. L. Drichko, A. M. Diakonov, I. Yu. Smirnov, Y. M. Galperin

The high-frequency conductivity of Si delta-doped GaAs/AlGaAs heterostructures is studied in the integer quantum Hall effect (QHE) regime, using acoustic methods. Both the real and the imaginary parts of the complex conductivity are determined from the experimentally observed magnetic field and temperature dependences of the velocity and the attenuation of a

Yung-Tae Kim, Nigel Goldenfeld, Jonathan Dantzig

We compute time-dependent solutions of the sharp-interface model of dendritic solidification in two dimensions by using a level set method. The steady-state results are in agreement with solvability theory. Solutions obtained from the level set algorithm are compared with dendritic growth simulations performed using a phase-field model and the two methods ar

Behnam Farid

By strictly adhering to the microscopic theory of composite fermions (CFs) for the Landau-level filling fractions ν_e = p/(2 p + 1), we reproduce, with remarkable accuracy, the surface-acoustic-wave (SAW)-based experimental results by Willett and co-workers concerning two-dimensional electron systems with ν_e close to 1/2. Our results imply that the electron

I. M. Khalatnikov, A. Yu. Kamenshchik

The paper was withdrawn by the authors

Yanqin Wu

Combination frequencies are observed in the Fourier spectra of pulsating DA and DB white dwarfs. They appear at sums and differences of frequencies associated with the stellar gravity-modes. Brickhill (1992) proposed that the combination frequencies result from mixing of the eigenmode signals as the surface convection zone varying in depth when undergoing pu

S. Capozziello, S. De Martino, S. De Siena, F. Guerra

We derive, in order of magnitude, the observed astrophysical and cosmological scales in the Universe, from neutron stars to superclusters of galaxies, up to, asymptotically, the observed radius of the Universe. This result is obtained by introducing a recursive scheme of alternating hierachical mechanisms of three-dimensional and two-dimensional close packin

Sune Toft, Jens Hjorth, Ingunn Burud

We present UBVRIz' photometry of the gravitational lens candidate CLASS B1152+119 obtained with the Nordic Optical Telescope. The two QSO components are resolved in the B, V, R, I and z' bands confirming the lensing nature of the system. The z=0.44 lens galaxy is clearly detected in B, R, I and z' and its position is found to be almost coincident

A. M. Fridman, O. V. Khoruzhii, E. V. Polyachenko, A. V. Zasov

We report detection of giant cyclonic vortices in the gaseous disc of the spiral galaxy NGC 3631 in the reference frame rotating with the spiral pattern. A presence of such structures was predicted by the authors for galaxies, where the radial gradient of the perturbed velocity exceeds that of the rotational velocity. This situation really takes place in NGC

Gavin Ramsay, Stephen Potter, Mark Cropper, David A. H. Buckley

We present simultaneous optical polarimetry and X-ray data of the near synchronous polar RX J2115-5840. We model the polarisation data using the Stokes imaging technique of Potter et al. We find that the data are best modelled using a relatively high binary inclination and a small angle between the magnetic and spin axes. We find that for all spin-orbit beat

M. Rieutord, T. Roudier, J. M. Malherbe, F. Rincon

We present arguments which show that in all likelihood mesogranulation is not a true scale of solar convection but the combination of the effects of both highly energetic granules, which give birth to strong positive divergences (SPDs) among which we find exploders, and averaging effects of data processing. The important role played by SPDs in horizontal vel

C. Zurita, J. Casares, T. Shahbaz, P. A. Charles

We present optical photometry of the X-ray transient XTE J2123-058, obtained in July-October 1998. The light curves are strongly modulated on the 5.95hrs orbital period, and exhibit dramatic changes in amplitude and form during the decline. We used synthetic models which include the effect of partial eclipses and X-ray heating effects, to estimate the system

E. Franciosini, S. Randich, R. Pallavicini

NGC 3532 is a very rich southern open cluster of age ~200-350 Myr; it is therefore a good candidate to investigate the X-ray activity-age-rotation relationship at ages intermediate between the Pleiades and the Hyades, where, to our knowledge, X-rays studies exist for only one cluster (NGC 6475). We have performed an X-ray study of NGC 3532 using HRI observat

D. R. Marlow, D. Rusin, N. Jackson, P. N. Wilkinson

Spectroscopic observations of a sample of 42 flat-spectrum radio sources from the Cosmic Lens All-Sky Survey (CLASS) have yielded a mean redshift of $<z> = 1.27$ with an RMS spread of 0.95, at a completeness level of 64%. The sample consists of sources with a 5-GHz flux density of 25-50 mJy, making it the faintest flat-spectrum radio sample for which the red

G. H. Moriarty-Schieven, J. A. Powers, H. M. Butner, P. G. Wannier

L1551NE is a very young (class 0 or I) low-mass protostar located close to the well-studied L1551 IRS5. We present here evidence, from 1.3mm continuum interferometric observations at ~1&#39;&#39; resolution, for a binary companion to L1551NE. The companion, whose 1.3mm flux density is ~1/3 that of the primary component, is located 1.43&#39;&#39; (~230 A.U. a

M. Chiba, T. C. Beers

(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H] <= -0.6, on the basis of a recently revised and supplemented catalog of metal-poor stars selected without kinematic bias (Beers et al. 2000). This sample, having available proper motions, radial velocities, and distance estimates fo

Christopher Sneden, John J. Cowan, Inese I. Ivans, George M. Fuller

First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor (UMP; [Fe/H] = -3.1) halo field giant star CS 22892-052. Using new high resolution, high signal-to-noise spectra, abundances of more than 30 neutron-capture elements (Z>30) have been determined. Six elements in the 40<Z<56 domain (Nb, Ru, Rh, Pd, Ag and Cd

Branislav K. Nikolic

The statistics of eigenfunction amplitudes are studied in mesoscopic disordered electron systems of finite size. The exact eigenspectrum and eigenstates are obtained by solving numerically Anderson Hamiltonian on a three-dimensional lattice for different strengths of disorder introduced either in the potential on-site energy (``diagonal&#39;&#39;) or in the

J. P. Bernstein, Suketu P. Bhavsar

The brightest, or first-ranked, galaxies (BCGs) in rich clusters show a very small dispersion in luminosity, making them excellent standard candles. This small dispersion has raised questions about the nature of BCGs. Are they simply the extremes of normal galaxies formed via a stochastic process, or do they belong to a special class of atypical objects? Arg

Andrzej Czarnecki, William J. Marciano

The utility of polarized electron beams for precision electroweak studies is described. Parity violating Moller scattering asymmetries in e-e- --> e-e- are discussed. Effects of electroweak radiative corrections and the running sin^2(theta_W(Q^2)) are reviewed. The sensitivity of E158 (a fixed target e-e- experiment at SLAC) and future e-e- collider studies

Detlef Lehmann

In many field theoretical models one has to resum two- and four-legged subdiagrams in order to determine their behaviour. In this article we present a novel formalism which does this in a nice way. It is based on the central limit theorem of probability and an inversion formula for matrices which is obtained by repeated application of the Feshbach projection

K. Tanaka, F. Marsiglio

We test the Anderson prescription [1], a BCS formalism for describing superconductivity in inhomogeneous systems, and compare results with those obtained from the Bogoliubov-de Gennes formalism, using the attractive Hubbard model with surfaces and nonmagnetic impurities. The Anderson approach captures the essential features of the spatial variation of the ga

J. A. Pons, S. Reddy, P. J. Ellis, M. Prakash

We study the equation of state (EOS) of kaon-condensed matter including the effects of temperature and trapped neutrinos. It is found that the order of the phase transition to a kaon-condensed phase, and whether or not Gibbs&#39; rules for phase equilibrium can be satisfied in the case of a first order transition, depend sensitively on the choice of the kaon

N. R. Kolb, A. W. Rauf, R. Igarashi, D. L. Hornidge

Cross sections for quasi-free Compton scattering from the deuteron were measured for incident energies of 236--260 MeV at the laboratory angle -135 degrees. The recoil nucleons were detected in a liquid-scintillator array situated at 20 degrees. The measured differential cross sections were used, with the calculations of Levchuk et al., to determine the pola

C. Bachas, M. Douglas, C. Schweigert

We explain how D-branes on group manifolds are stabilized against shrinking by quantized worldvolume U(1) fluxes. Starting from the Born-Infeld action in the case of the SU(2) group manifold we derive the masses, multiplicities and spectrum of small fluctuations of these branes, and show that they agree exactly with the predictions of conformal field theory,

T. Gilbert, J. R. Dorfman, P. Gaspard

The theory of entropy production in nonequilibrium, Hamiltonian systems, previously described for steady states using partitions of phase space, is here extended to time dependent systems relaxing to equilibrium. We illustrate the main ideas by using a simple multibaker model, with some nonequilibrium initial state, and we study its progress toward equilibri

M. Peloso, L. Sorbo

Non-perturbative production of fermions after chaotic inflation has been the object of several studies in the very recent past. However, the results in the most interesting case of production of massive fermions in an expanding Universe were so far known only numerically. We provide very simple and readable analytical formulae, both for the spectra of the cr

Ruth Gregory, Valery A. Rubakov, Sergei M. Sibiryakov

In the framework of a five-dimensional three-brane model with quasi-localized gravitons we evaluate metric perturbations induced on the positive tension brane by matter residing thereon. We find that at intermediate distances, the effective four-dimensional theory coincides, up to small corrections, with General Relativity. This is in accord with Csaki, Erli

P. Sebbah, R. Pnini, A. Z. Genack

Measurements of the microwave field transmitted through a random medium allows direct access to the field correlation function, whose complex square is the short range or C1 contribution to the intensity correlation function C. The frequency and spatial correlation function are compared to their Fourier pairs, the time of flight distribution and the specific

Dmitri Antonov

String representation of the Wilson loop in 3D Abelian-projected SU(3)-gluodynamics is constructed in the approximation that Abelian-projected monopoles form a gas. Such an assumption is much weaker than the standard one, demanding the monopole condensation. It is demonstrated that the summation over world sheets, bounded by the contour of the Wilson loop, i

J. Bartels, K. Golec-Biernat, K. Peters

We investigate the influence of higher twist corrections to deep inelastic structure functions in the low-$Q^2$ and small-$x$ HERA region. We review the general features of the lowest-order QCD diagrams which contribute to twist-4 at small-$x$, in particular the sign structure of longitudinal and transverse structure functions which offers the possibility of

David A. Lowe

Black hole no-hair theorems are proven using inequalities that govern the radial dependence of spherically symmetric configurations of matter fields. In this paper, we analyze the analogous inequalities for geometries dual to renormalization group flows via the AdS/CFT correspondence. These inequalities give much useful information about the qualitative prop

P. W. Lucas, P. F. Roche

We describe the results of a very deep imaging survey of the Trapezium Cluster in the IJH bands, using the UKIRT high resolution camera UFTI. Approximately 32% of the 515 point sources detected are brown dwarf candidates, including several free floating objects with masses below the Deuterium burning (planetary) threshold at 0.013 solar masses, which are det

D. Bernard, A. LeClair

We use quantum field theory methods to study the network model for the spin quantum hall transition. When the couplings are fine tuned in a certain way, the spin and charge degrees of freedom, corresponding to the supercurrent algebras su(2) and osp(2|2) respectively, decouple in the renormalization group flow. The infrared fixed point of this simpler theory

Yu. V. Tarasov

A method is proposed for studying wave and particle transport in disordered waveguide systems of dimension higher than unity by means of exact one-dimensionalization of the dynamic equations in the mode representation. As a particular case, the T=0 conductance of a two-dimensional quantum wire is calculated, which exhibits ohmic behaviour, with length-depend

Hiroshi Shimahara

We propose a phase diagram of quasi-low-dimensional type II superconductors in parallel magnetic fields, when antiferromagnetic fluctuations contribute to the pairing interactions. We point out that pairing interactions mediated by antiferromagnetic fluctuations necessarily include both singlet channels and triplet channels as attractive interactions. Usuall

J. L. Flores, M. Sanchez

Given two points of a Generalized Robertson-Walker spacetime, the existence, multiplicity and causal character of geodesic connecting them is characterized. Conjugate points of such geodesics are related to conjugate points of geodesics on the fiber, and Morse-type relations are obtained. Applications to bidimensional spacetimes and to GRW spacetimes satisfy

U. Leonhardt, P. Piwnicki

Leonhardt and Piwnicki reply to Visser&#39;s ``Comment on `Relativistic Effects of Light in Moving Media with Extremely Low Group Velocity&#39; &#39;&#39;.

A. A. Sen, N. Banerjee

Gravitational field of a nonstatic global string has been studied in the context of Brans-Dicke theory of gravity. Both the metric components and the BD scalar field are assumed to be nonseparable functions of time and space.The spacetime may or may not have any singularity at a finite distance from the string core but the singularity at a particular time al

Coryn A. L. Bailer-Jones

Large scale, deep survey missions such as GAIA will collect enormous amounts of data on a significant fraction of the stellar content of our Galaxy. These missions will require a careful optimisation of their observational systems in order to maximise their scientific return, and will require reliable and automated techniques for parametrizing the very large

D. C. Johnston, T. Saito, M. Azuma, M. Takano

The magnetic susceptibilities chi versus temperature T of powders and single crystals of the ambient-pressure (AP) and high-pressure (HP) phases of (VO)_{2}P_{2}O_{7} are analyzed using an accurate theoretical prediction of chi(T, J1, J2) for the spin-1/2 antiferromagnetic alternating-exchange (J1, J2) Heisenberg chain. The results are consistent with recent

R. de Mello Koch, A. Jevicki, M. Mihailescu, R. Tatar

We describe numerical methods for constructing lump solutions in open string field theory. According to Sen, these lumps represent lower dimensional Dp-Branes and numerical evaluation of their energy can be compared with the expected value for the tension. We take particular care of all higher derivative terms inherent in Witten&#39;s version of open string

Aiichi Iwazaki

We propose a model in which ultra high energy cosmic rays are produced by collisions between neutron stars and axion stars. The acceleration of such a cosmic ray is made by the electric field, $\sim 10^{15} (B/10^{12} {G}) {eV} {cm}^{-1}$, which is induced in an axion star by the strong magnetic field $B>10^{12}$ G of a neutron star. As we have shown previou

John H. Reina, Luis Quiroga, Neil F. Johnson

We propose a nanostructure switch based on nuclear magnetic resonance (NMR) which offers reliable quantum gate operation, an essential ingredient for building a quantum computer. The nuclear resonance is controlled by the magic number transitions of a few-electron quantum dot in an external magnetic field.

James Liebert, I. Neill Reid, Adam Burrows, Adam J. Burgasser

A Keck~II low resolution spectrum shortward of ome-micron is presented for SDSS 1624+0029, the first field methane or T dwarf discovered in the Sloan Digital Sky Survey. Significant flux is detected down to the spectrum&#39;s short wavelength limit of 6200Å. The spectrum exhibits a broad absorption feature centered at 7700Å, which we interpret as the K~I 766

Aneesh V. Manohar, Iain W. Stewart

The one-loop QCD heavy quark potential is computed to order v^2 in the color singlet and octet channels. Several errors in the previous literature are corrected. To be consistent with the velocity power counting, the full dependence on |p&#39; + p|/|p&#39; - p| is kept. The matching conditions for the NRQCD one-loop potential are computed by comparing the QC

Ivan H. Deutsch, Gavin K. Brennen, Poul S. Jessen

We present a proposal for quantum information processing with neutral atoms trapped in optical lattices as qubits. Initialization and coherent control of single qubits can be achieved with standard laser cooling and spectroscopic techniques. We consider entangling two-qubit logic gates based on optically induced dipole-dipole interactions, calculating a figu

M. Bordag, B. Geyer, G. L. Klimchitskaya, V. M. Mostepanenko

We find the joint effect of non-zero temperature and finite conductivity onto the Casimir force between real metals. Configurations of two parallel plates and a sphere (lens) above a plate are considered. Perturbation theory in two parameters (the relative temperature and the relative penetration depth of zero point oscillations into the metal) is developed.

G. B. Tupper

A pedagological introduction to effective field theory is presented.

D. Sweet, E. Ott

Using examples we test formulae previously conjectured to give the fractal information dimension of chaotic repellors and their stable and unstable manifolds in ``typical&#39;&#39; dynamical systems in terms of the Lyapunov exponents and the characteristic escape time from the repellor. Our main example, a three-dimensional chaotic scattering billiard, yield

L. Kaplan

We study the effects of short-time classical dynamics on the distribution of Coulomb blockade peak heights in a chaotic quantum dot. The location of one or both leads relative to the short unstable orbits, as well as relative to the symmetry lines, can have large effects on the moments and on the head and tail of the conductance distribution. We study these

I. M. Krichever, S. P. Novikov

We review basic ideas and basic examples of the theory of the inverse spectral problems.

Cristopher Moore, John Michael Robson

It is well-known that the question of whether a given finite region can be tiled with a given set of tiles is NP-complete. We show that the same is true for the right tromino and square tetromino on the square lattice, or for the right tromino alone. In the process, we show that Monotone 1-in-3 Satisfiability is NP-complete for planar cubic graphs. In higher

Haisheng Li

We generalize Feigin and Miwa&#39;s construction of extended vertex operator (super)algebras $A_{k}(sl(2))$ for other types of simple Lie algebras. For all the constructed extended vertex operator (super)algebras, irreducible modules are classified, complete reducibility of every module is proved and fusion rules are determined modulo the fusion rules for ve

David De Wit

Partitioning a graph into three pieces, with two of them large and connected, and the third a small ``separator&#39;&#39; set, is useful for improving the performance of a number of combinatorial algorithms. This is done using the second eigenvector of a matrix defined solely in terms of the incidence matrix, called the graph Laplacian. For sparse graphs, th

S. Khoroshkin, A. LeClair, S. Pakuliak

The goal of this paper is to analyse the method of angular quantization for the Sine-Gordon model at the free fermion point, which is one of the most investigated models of the two-dimensional integrable field theories. The angular quantization method (see hep-th/9707091) is a continuous analog of the Baxter&#39;s corner transfer matrix method. Investigating

R. Marotta, F. Pezzella

The {\em cutting and sewing} procedure is used for getting two-loop order Feynman diagrams of $Φ^{4}$-theory with an internal SU(N) symmetry group, starting from tachyon amplitudes of the open bosonic string theory. In a suitably defined field theory limit, we reproduce the field theory amplitudes properly normalized and expressed in the Schwinger parametriz

A. H. Chamseddine, W. A. Sabra

The U(1) gauged version of the Strominger-Vafa five dimensional N=2 supergravity with one vector multiplet is obtained via dimensional reduction from the N=1 ten dimensional supergavity. Using such explicit relation between the gauged supergravity theory and ten dimensional supergravity, all known solutions of the five dimensional theory can be lifted up to

O-Kab Kwon, Choonkyu Lee, Hyunsoo Min

If background fields are soft on the scale set by mass of the particle involved, a reliable approximation to the field-theoretic one-loop effective action is obtained by a systematic large mass expansion involving higher-order Seeley-DeWitt coefficients. Moreover, if the small mass limit of the effective action in a particular background has been found by so

J. Manjavidze, A. Sissakian

The `strong-coupling&#39; perturbation theory over the inverse interaction constant $1/g$ near the nontrivial solution of Lagrange equation is formulated. The ordinary `week-coupling&#39; perturbation theory over $g$ is described also to compare both perturbation theories. The `strong-coupling&#39; perturbation theory is developed by unitary mapping of the q

G. Arutyunov, S. Frolov

It is shown that a nonlinear derivative-dependent transformation of gravity fields changes correlation functions in a boundary CFT, and, therefore, corresponds to a change of a basis of operators in the CFT. It is argued that only non-renormalized structures in correlation functions can be changed by such a field transformation, and that the study of the res

Igor Pesando

We discuss the classical solutions of the equations of motion and the possible boundary condition for a bosonic string with Kalb-Ramond background in AdS3. It turns out that there exists three different physical sectors and that it is also possible to describe the motion on an extremal black hole background. The existence of three sectors clearly shows how o

Jorgen Rasmussen

We present a new and asymmetric N=4 superconformal algebra for arbitrary central charge, thus completing our recent work on its classical analogue with vanishing central charge. Besides the Virasoro generator and 4 supercurrents, the algebra consists of an internal SL(2) \otimes U(1) Kac-Moody algebra in addition to two spin 1/2 fermions and a bosonic scalar

Pei-Ming Ho

We study the notion of twisted bundles on noncommutative space. Due to the existence of projective operators in the algebra of functions on the noncommutative space, there are twisted bundles with non-constant dimension. The U(1) instanton solution of Nekrasov and Schwarz is such an example. As a mathematical motivation for not excluding such bundles, we fin

R. Hofmann, T. Gutsche, M. Schumann, R. D. Viollier

An alternative to introducing and subsequently renormalizing classical parameters in the expression for the vacuum energy of the MIT bag for quarks is proposed in the massless case by appealing to the QCD trace anomaly and scale separation due to asymptotic freedom. The explicit inclusion of gluons implies an unrealistically low separation scale.

Stephen L. Adler

We discuss the possibility that fermionic condensates arise from the dominance of scalar exchange forces over vector gluon exchange. When a scalar in the adjoint representation is exchanged in the reaction $A+A \to A+A$, the usual most attractive channel (MAC) rule is reversed in sign, with the consequence that the formation of a condensate with the largest

David W. Gerdes

I discuss the motivation and physics potential of an electron-positron linear collider with a center-of-mass energy at the 1 TeV scale, in light of what we may expect to learn with the LHC. The comparison is illustrated with examples drawn from Higgs physics, top quark physics, and the search for large extra spacetime dimensions.

Luca Trentadue, Michela Verbeni

We extend the approach of Dolgov and Zakharov to the axial anomaly to study polarized radiative decays. We analyse the pattern of mass singularity cancellation in the corresponding decay rates. We compare polarized and unpolarized cases. The cancellation of the infrared and collinear singularities is verified to all powers of the lepton mass for the $π^+$ an

W. L. van Neerven

We present some techniques which have been developed recently or in the recent past to compute Feynman graphs beyond one-loop order. These techniques are useful to compute the three-loop splitting functions in QCD and to obtain the complete second order QED corrections to Bhabha scattering.

J. Manjavidze, A. Sissakian

It is argued considering multiple production in the deep inelastic scattering kinematics that the very high multiplicity events are extremely sensitive to the low-x partons density.

J. Manjavidze, A. Sissakian

The consequence of vacuum instability against particles creation is described using lattice gas model. It is shown that the tail of multiplicity distribution should decrees slower than any power of $\exp\{-n\}$, but faster than any power of $1/n$ if the vacuum is unstable against particles creation.

J. Manjavidze, A. Sissakian

The generating functionals (GF) method in Bogolyubov&#39;s formulation and its application for particle physics is considered. Effectiveness of the method is illustrated by two examples. So, GF method can be used as the technical trick solving the infinite sequence of algebraic equations. We will consider the example, where GF allows express the multiplicity

T. Teshima, T. Sakai

We analyze the atmospheric neutrino experiments of Super-Kamiokande (830-920 live days) using the three-flavor neutrino framework with the mass hierarchy m_1 nearly equal m_2 << m_3. We study the sub-GeV, multi- GeV neutrinos and upward through-going and stopping muons zenith angle distributions taking account of the Earth matter effects thoroughly. We obtai